Move calculate state to the state package (#121)
This commit is contained in:
Mark Haines
GitHub
parent
db23640f69
commit
a96b124158
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@ -30,15 +30,6 @@ type RoomEventDatabase interface {
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// Returns an error if the there is an error talking to the database
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// or if the event IDs aren't in the database.
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StateEntriesForEventIDs(eventIDs []string) ([]types.StateEntry, error)
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// Lookup the Events for a list of numeric event IDs.
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// Returns a sorted list of events.
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Events(eventNIDs []types.EventNID) ([]types.Event, error)
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// Lookup the state of a room at each event for a list of string event IDs.
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// Returns an error if there is an error talking to the database
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// or if the room state for the event IDs aren't in the database
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StateAtEventIDs(eventIDs []string) ([]types.StateAtEvent, error)
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// Store the room state at an event in the database
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AddState(roomNID types.RoomNID, stateBlockNIDs []types.StateBlockNID, state []types.StateEntry) (types.StateSnapshotNID, error)
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// Set the state at an event.
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SetState(eventNID types.EventNID, stateNID types.StateSnapshotNID) error
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// Lookup the latest events in a room in preparation for an update.
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@ -98,7 +89,7 @@ func processRoomEvent(db RoomEventDatabase, ow OutputRoomEventWriter, input api.
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}
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} else {
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// We haven't been told what the state at the event is so we need to calculate it from the prev_events
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if stateAtEvent.BeforeStateSnapshotNID, err = calculateAndStoreStateBeforeEvent(db, event, roomNID); err != nil {
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if stateAtEvent.BeforeStateSnapshotNID, err = state.CalculateAndStoreStateBeforeEvent(db, event, roomNID); err != nil {
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return err
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}
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}
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@ -100,7 +100,7 @@ func doUpdateLatestEvents(
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for i := range newLatest {
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latestStateAtEvents[i] = newLatest[i].StateAtEvent
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}
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newStateNID, err := calculateAndStoreStateAfterEvents(db, roomNID, latestStateAtEvents)
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newStateNID, err := state.CalculateAndStoreStateAfterEvents(db, roomNID, latestStateAtEvents)
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if err != nil {
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return err
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}
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@ -1,368 +0,0 @@
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// Copyright 2017 Vector Creations Ltd
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package input
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import (
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"fmt"
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"github.com/matrix-org/dendrite/roomserver/state"
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"github.com/matrix-org/dendrite/roomserver/types"
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"github.com/matrix-org/gomatrixserverlib"
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"github.com/matrix-org/util"
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"github.com/prometheus/client_golang/prometheus"
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"sort"
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"time"
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)
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var calculateStateDurations = prometheus.NewSummaryVec(
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prometheus.SummaryOpts{
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Namespace: "dendrite",
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Subsystem: "roomserver",
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Name: "calculate_state_duration_microseconds",
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Help: "How long it takes to calculate the state after a list of events",
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},
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// Takes two labels:
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// algorithm:
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// The algorithm used to calculate the state or the step it failed on if it failed.
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// Labels starting with "_" are used to indicate when the algorithm fails halfway.
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// outcome:
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// Whether the state was successfully calculated.
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//
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// The possible values for algorithm are:
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// empty_state -> The list of events was empty so the state is empty.
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// no_change -> The state hasn't changed.
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// single_delta -> There was a single event added to the state in a way that can be encoded as a single delta
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// full_state_no_conflicts -> We created a new copy of the full room state, but didn't enounter any conflicts
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// while doing so.
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// full_state_with_conflicts -> We created a new copy of the full room state and had to resolve conflicts to do so.
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// _load_state_block_nids -> Failed loading the state block nids for a single previous state.
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// _load_combined_state -> Failed to load the combined state.
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// _resolve_conflicts -> Failed to resolve conflicts.
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[]string{"algorithm", "outcome"},
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)
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var calculateStatePrevEventLength = prometheus.NewSummaryVec(
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prometheus.SummaryOpts{
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Namespace: "dendrite",
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Subsystem: "roomserver",
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Name: "calculate_state_prev_event_length",
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Help: "The length of the list of events to calculate the state after",
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},
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[]string{"algorithm", "outcome"},
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)
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var calculateStateFullStateLength = prometheus.NewSummaryVec(
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prometheus.SummaryOpts{
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Namespace: "dendrite",
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Subsystem: "roomserver",
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Name: "calculate_state_full_state_length",
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Help: "The length of the full room state.",
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},
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[]string{"algorithm", "outcome"},
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)
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var calculateStateConflictLength = prometheus.NewSummaryVec(
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prometheus.SummaryOpts{
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Namespace: "dendrite",
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Subsystem: "roomserver",
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Name: "calculate_state_conflict_state_length",
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Help: "The length of the conflicted room state.",
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},
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[]string{"algorithm", "outcome"},
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)
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type calculateStateMetrics struct {
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algorithm string
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startTime time.Time
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prevEventLength int
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fullStateLength int
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conflictLength int
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}
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func (c *calculateStateMetrics) stop(stateNID types.StateSnapshotNID, err error) (types.StateSnapshotNID, error) {
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var outcome string
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if err == nil {
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outcome = "success"
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} else {
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outcome = "failure"
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}
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endTime := time.Now()
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calculateStateDurations.WithLabelValues(c.algorithm, outcome).Observe(
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float64(endTime.Sub(c.startTime).Nanoseconds()) / 1000.,
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)
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calculateStatePrevEventLength.WithLabelValues(c.algorithm, outcome).Observe(
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float64(c.prevEventLength),
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)
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calculateStateFullStateLength.WithLabelValues(c.algorithm, outcome).Observe(
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float64(c.fullStateLength),
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)
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calculateStateConflictLength.WithLabelValues(c.algorithm, outcome).Observe(
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float64(c.conflictLength),
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)
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return stateNID, err
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}
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func init() {
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prometheus.MustRegister(
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calculateStateDurations, calculateStatePrevEventLength,
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calculateStateFullStateLength, calculateStateConflictLength,
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)
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}
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// calculateAndStoreState calculates a snapshot of the state of a room before an event.
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// Stores the snapshot of the state in the database.
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// Returns a numeric ID for the snapshot of the state before the event.
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func calculateAndStoreStateBeforeEvent(
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db RoomEventDatabase, event gomatrixserverlib.Event, roomNID types.RoomNID,
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) (types.StateSnapshotNID, error) {
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// Load the state at the prev events.
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prevEventRefs := event.PrevEvents()
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prevEventIDs := make([]string, len(prevEventRefs))
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for i := range prevEventRefs {
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prevEventIDs[i] = prevEventRefs[i].EventID
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}
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prevStates, err := db.StateAtEventIDs(prevEventIDs)
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if err != nil {
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return 0, err
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}
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// The state before this event will be the state after the events that came before it.
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return calculateAndStoreStateAfterEvents(db, roomNID, prevStates)
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}
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// calculateAndStoreStateAfterEvents finds the room state after the given events.
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// Stores the resulting state in the database and returns a numeric ID for that snapshot.
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func calculateAndStoreStateAfterEvents(db RoomEventDatabase, roomNID types.RoomNID, prevStates []types.StateAtEvent) (types.StateSnapshotNID, error) {
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metrics := calculateStateMetrics{startTime: time.Now(), prevEventLength: len(prevStates)}
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if len(prevStates) == 0 {
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// 2) There weren't any prev_events for this event so the state is
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// empty.
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metrics.algorithm = "empty_state"
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return metrics.stop(db.AddState(roomNID, nil, nil))
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}
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if len(prevStates) == 1 {
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prevState := prevStates[0]
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if prevState.EventStateKeyNID == 0 {
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// 3) None of the previous events were state events and they all
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// have the same state, so this event has exactly the same state
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// as the previous events.
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// This should be the common case.
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metrics.algorithm = "no_change"
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return metrics.stop(prevState.BeforeStateSnapshotNID, nil)
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}
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// The previous event was a state event so we need to store a copy
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// of the previous state updated with that event.
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stateBlockNIDLists, err := db.StateBlockNIDs([]types.StateSnapshotNID{prevState.BeforeStateSnapshotNID})
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if err != nil {
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metrics.algorithm = "_load_state_blocks"
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return metrics.stop(0, err)
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}
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stateBlockNIDs := stateBlockNIDLists[0].StateBlockNIDs
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if len(stateBlockNIDs) < maxStateBlockNIDs {
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// 4) The number of state data blocks is small enough that we can just
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// add the state event as a block of size one to the end of the blocks.
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metrics.algorithm = "single_delta"
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return metrics.stop(db.AddState(
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roomNID, stateBlockNIDs, []types.StateEntry{prevState.StateEntry},
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))
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}
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// If there are too many deltas then we need to calculate the full state
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// So fall through to calculateAndStoreStateAfterManyEvents
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}
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return calculateAndStoreStateAfterManyEvents(db, roomNID, prevStates, metrics)
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}
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// maxStateBlockNIDs is the maximum number of state data blocks to use to encode a snapshot of room state.
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// Increasing this number means that we can encode more of the state changes as simple deltas which means that
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// we need fewer entries in the state data table. However making this number bigger will increase the size of
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// the rows in the state table itself and will require more index lookups when retrieving a snapshot.
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// TODO: Tune this to get the right balance between size and lookup performance.
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const maxStateBlockNIDs = 64
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// calculateAndStoreStateAfterManyEvents finds the room state after the given events.
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// This handles the slow path of calculateAndStoreStateAfterEvents for when there is more than one event.
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// Stores the resulting state and returns a numeric ID for the snapshot.
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func calculateAndStoreStateAfterManyEvents(
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db RoomEventDatabase, roomNID types.RoomNID, prevStates []types.StateAtEvent, metrics calculateStateMetrics,
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) (types.StateSnapshotNID, error) {
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// Conflict resolution.
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// First stage: load the state after each of the prev events.
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combined, err := state.LoadCombinedStateAfterEvents(db, prevStates)
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if err != nil {
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metrics.algorithm = "_load_combined_state"
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return metrics.stop(0, err)
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}
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// Collect all the entries with the same type and key together.
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// We don't care about the order here because the conflict resolution
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// algorithm doesn't depend on the order of the prev events.
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// Remove duplicate entires.
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combined = combined[:util.SortAndUnique(stateEntrySorter(combined))]
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// Find the conflicts
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conflicts := findDuplicateStateKeys(combined)
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var state []types.StateEntry
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if len(conflicts) > 0 {
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metrics.conflictLength = len(conflicts)
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// 5) There are conflicting state events, for each conflict workout
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// what the appropriate state event is.
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// Work out which entries aren't conflicted.
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var notConflicted []types.StateEntry
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for _, entry := range combined {
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if _, ok := stateEntryMap(conflicts).lookup(entry.StateKeyTuple); !ok {
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notConflicted = append(notConflicted, entry)
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}
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}
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resolved, err := resolveConflicts(db, notConflicted, conflicts)
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if err != nil {
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metrics.algorithm = "_resolve_conflicts"
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return metrics.stop(0, err)
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}
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metrics.algorithm = "full_state_with_conflicts"
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state = resolved
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} else {
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metrics.algorithm = "full_state_no_conflicts"
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// 6) There weren't any conflicts
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state = combined
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}
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metrics.fullStateLength = len(state)
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// TODO: Check if we can encode the new state as a delta against the
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// previous state.
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return metrics.stop(db.AddState(roomNID, nil, state))
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}
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// loadStateEvents loads the matrix events for a list of state entries.
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// Returns a list of state events in no particular order and a map from string event ID back to state entry.
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// The map can be used to recover which numeric state entry a given event is for.
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// Returns an error if there was a problem talking to the database.
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func loadStateEvents(db RoomEventDatabase, entries []types.StateEntry) ([]gomatrixserverlib.Event, map[string]types.StateEntry, error) {
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eventNIDs := make([]types.EventNID, len(entries))
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for i := range entries {
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eventNIDs[i] = entries[i].EventNID
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}
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events, err := db.Events(eventNIDs)
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if err != nil {
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return nil, nil, err
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}
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eventIDMap := map[string]types.StateEntry{}
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result := make([]gomatrixserverlib.Event, len(entries))
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for i := range entries {
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event, ok := eventMap(events).lookup(entries[i].EventNID)
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if !ok {
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panic(fmt.Errorf("Corrupt DB: Missing event numeric ID %d", entries[i].EventNID))
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}
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result[i] = event.Event
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eventIDMap[event.Event.EventID()] = entries[i]
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}
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return result, eventIDMap, nil
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}
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// resolveConflicts resolves a list of conflicted state entries. It takes two lists.
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// The first is a list of all state entries that are not conflicted.
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// The second is a list of all state entries that are conflicted
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// A state entry is conflicted when there is more than one numeric event ID for the same state key tuple.
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// Returns a list that combines the entries without conflicts with the result of state resolution for the entries with conflicts.
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// The returned list is sorted by state key tuple.
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// Returns an error if there was a problem talking to the database.
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func resolveConflicts(db RoomEventDatabase, notConflicted, conflicted []types.StateEntry) ([]types.StateEntry, error) {
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// Load the conflicted events
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conflictedEvents, eventIDMap, err := loadStateEvents(db, conflicted)
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if err != nil {
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return nil, err
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}
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// Work out which auth events we need to load.
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needed := gomatrixserverlib.StateNeededForAuth(conflictedEvents)
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// Find the numeric IDs for the necessary state keys.
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var neededStateKeys []string
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neededStateKeys = append(neededStateKeys, needed.Member...)
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neededStateKeys = append(neededStateKeys, needed.ThirdPartyInvite...)
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stateKeyNIDMap, err := db.EventStateKeyNIDs(neededStateKeys)
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if err != nil {
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return nil, err
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}
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// Load the necessary auth events.
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tuplesNeeded := stateKeyTuplesNeeded(stateKeyNIDMap, needed)
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var authEntries []types.StateEntry
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for _, tuple := range tuplesNeeded {
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if eventNID, ok := stateEntryMap(notConflicted).lookup(tuple); ok {
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authEntries = append(authEntries, types.StateEntry{tuple, eventNID})
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}
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}
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authEvents, _, err := loadStateEvents(db, authEntries)
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if err != nil {
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return nil, err
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}
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// Resolve the conflicts.
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resolvedEvents := gomatrixserverlib.ResolveStateConflicts(conflictedEvents, authEvents)
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// Map from the full events back to numeric state entries.
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for _, resolvedEvent := range resolvedEvents {
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entry, ok := eventIDMap[resolvedEvent.EventID()]
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if !ok {
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panic(fmt.Errorf("Missing state entry for event ID %q", resolvedEvent.EventID()))
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}
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notConflicted = append(notConflicted, entry)
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}
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// Sort the result so it can be searched.
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sort.Sort(stateEntrySorter(notConflicted))
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return notConflicted, nil
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}
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// findDuplicateStateKeys finds the state entries where the state key tuple appears more than once in a sorted list.
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// Returns a sorted list of those state entries.
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func findDuplicateStateKeys(a []types.StateEntry) []types.StateEntry {
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var result []types.StateEntry
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// j is the starting index of a block of entries with the same state key tuple.
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j := 0
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for i := 1; i < len(a); i++ {
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// Check if the state key tuple matches the start of the block
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if a[j].StateKeyTuple != a[i].StateKeyTuple {
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// If the state key tuple is different then we've reached the end of a block of duplicates.
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// Check if the size of the block is bigger than one.
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// If the size is one then there was only a single entry with that state key tuple so we don't add it to the result
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if j+1 != i {
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// Add the block to the result.
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result = append(result, a[j:i]...)
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}
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// Start a new block for the next state key tuple.
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j = i
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}
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}
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// Check if the last block with the same state key tuple had more than one event in it.
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if j+1 != len(a) {
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result = append(result, a[j:]...)
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}
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return result
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}
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type stateEntrySorter []types.StateEntry
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func (s stateEntrySorter) Len() int { return len(s) }
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func (s stateEntrySorter) Less(i, j int) bool { return s[i].LessThan(s[j]) }
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func (s stateEntrySorter) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
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@ -35,9 +35,6 @@ type RoomserverQueryAPIDatabase interface {
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// Lookup event references for the latest events in the room and the current state snapshot.
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// Returns an error if there was a problem talking to the database.
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LatestEventIDs(roomNID types.RoomNID) ([]gomatrixserverlib.EventReference, types.StateSnapshotNID, error)
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// Lookup the Events for a list of numeric event IDs.
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// Returns a list of events sorted by numeric event ID.
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Events(eventNIDs []types.EventNID) ([]types.Event, error)
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}
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// RoomserverQueryAPI is an implementation of RoomserverQueryAPI
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@ -21,11 +21,19 @@ import (
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"github.com/matrix-org/dendrite/roomserver/types"
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"github.com/matrix-org/gomatrixserverlib"
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"github.com/matrix-org/util"
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"github.com/prometheus/client_golang/prometheus"
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"sort"
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"time"
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)
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// A RoomStateDatabase has the storage APIs needed to load state from the database
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type RoomStateDatabase interface {
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// Store the room state at an event in the database
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||||
AddState(roomNID types.RoomNID, stateBlockNIDs []types.StateBlockNID, state []types.StateEntry) (types.StateSnapshotNID, error)
|
||||
// Lookup the state of a room at each event for a list of string event IDs.
|
||||
// Returns an error if there is an error talking to the database
|
||||
// or if the room state for the event IDs aren't in the database
|
||||
StateAtEventIDs(eventIDs []string) ([]types.StateAtEvent, error)
|
||||
// Lookup the numeric IDs for a list of string event types.
|
||||
// Returns a map from string event type to numeric ID for the event type.
|
||||
EventTypeNIDs(eventTypes []string) (map[string]types.EventTypeNID, error)
|
||||
|
|
@ -45,6 +53,9 @@ type RoomStateDatabase interface {
|
|||
StateEntriesForTuples(stateBlockNIDs []types.StateBlockNID, stateKeyTuples []types.StateKeyTuple) (
|
||||
[]types.StateEntryList, error,
|
||||
)
|
||||
// Lookup the Events for a list of numeric event IDs.
|
||||
// Returns a sorted list of events.
|
||||
Events(eventNIDs []types.EventNID) ([]types.Event, error)
|
||||
}
|
||||
|
||||
// LoadStateAtSnapshot loads the full state of a room at a particular snapshot.
|
||||
|
|
@ -211,6 +222,21 @@ func DifferenceBetweeenStateSnapshots(db RoomStateDatabase, oldStateNID, newStat
|
|||
}
|
||||
}
|
||||
|
||||
// LoadStateAtSnapshotForStringTuples loads the state for a list of event type and state key pairs at a snapshot.
|
||||
// This is used when we only want to load a subset of the room state at a snapshot.
|
||||
// If there is no entry for a given event type and state key pair then it will be discarded.
|
||||
// This is typically the state before an event or the current state of a room.
|
||||
// Returns a sorted list of state entries or an error if there was a problem talking to the database.
|
||||
func LoadStateAtSnapshotForStringTuples(
|
||||
db RoomStateDatabase, stateNID types.StateSnapshotNID, stateKeyTuples []gomatrixserverlib.StateKeyTuple,
|
||||
) ([]types.StateEntry, error) {
|
||||
numericTuples, err := stringTuplesToNumericTuples(db, stateKeyTuples)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
return loadStateAtSnapshotForNumericTuples(db, stateNID, numericTuples)
|
||||
}
|
||||
|
||||
// stringTuplesToNumericTuples converts the string state key tuples into numeric IDs
|
||||
// If there isn't a numeric ID for either the event type or the event state key then the tuple is discarded.
|
||||
// Returns an error if there was a problem talking to the database.
|
||||
|
|
@ -247,21 +273,6 @@ func stringTuplesToNumericTuples(db RoomStateDatabase, stringTuples []gomatrixse
|
|||
return result, nil
|
||||
}
|
||||
|
||||
// LoadStateAtSnapshotForStringTuples loads the state for a list of event type and state key pairs at a snapshot.
|
||||
// This is used when we only want to load a subset of the room state at a snapshot.
|
||||
// If there is no entry for a given event type and state key pair then it will be discarded.
|
||||
// This is typically the state before an event or the current state of a room.
|
||||
// Returns a sorted list of state entries or an error if there was a problem talking to the database.
|
||||
func LoadStateAtSnapshotForStringTuples(
|
||||
db RoomStateDatabase, stateNID types.StateSnapshotNID, stateKeyTuples []gomatrixserverlib.StateKeyTuple,
|
||||
) ([]types.StateEntry, error) {
|
||||
numericTuples, err := stringTuplesToNumericTuples(db, stateKeyTuples)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
return loadStateAtSnapshotForNumericTuples(db, stateNID, numericTuples)
|
||||
}
|
||||
|
||||
// loadStateAtSnapshotForNumericTuples loads the state for a list of event type and state key pairs at a snapshot.
|
||||
// This is used when we only want to load a subset of the room state at a snapshot.
|
||||
// If there is no entry for a given event type and state key pair then it will be discarded.
|
||||
|
|
@ -305,6 +316,375 @@ func loadStateAtSnapshotForNumericTuples(
|
|||
return fullState, nil
|
||||
}
|
||||
|
||||
var calculateStateDurations = prometheus.NewSummaryVec(
|
||||
prometheus.SummaryOpts{
|
||||
Namespace: "dendrite",
|
||||
Subsystem: "roomserver",
|
||||
Name: "calculate_state_duration_microseconds",
|
||||
Help: "How long it takes to calculate the state after a list of events",
|
||||
},
|
||||
// Takes two labels:
|
||||
// algorithm:
|
||||
// The algorithm used to calculate the state or the step it failed on if it failed.
|
||||
// Labels starting with "_" are used to indicate when the algorithm fails halfway.
|
||||
// outcome:
|
||||
// Whether the state was successfully calculated.
|
||||
//
|
||||
// The possible values for algorithm are:
|
||||
// empty_state -> The list of events was empty so the state is empty.
|
||||
// no_change -> The state hasn't changed.
|
||||
// single_delta -> There was a single event added to the state in a way that can be encoded as a single delta
|
||||
// full_state_no_conflicts -> We created a new copy of the full room state, but didn't enounter any conflicts
|
||||
// while doing so.
|
||||
// full_state_with_conflicts -> We created a new copy of the full room state and had to resolve conflicts to do so.
|
||||
// _load_state_block_nids -> Failed loading the state block nids for a single previous state.
|
||||
// _load_combined_state -> Failed to load the combined state.
|
||||
// _resolve_conflicts -> Failed to resolve conflicts.
|
||||
[]string{"algorithm", "outcome"},
|
||||
)
|
||||
|
||||
var calculateStatePrevEventLength = prometheus.NewSummaryVec(
|
||||
prometheus.SummaryOpts{
|
||||
Namespace: "dendrite",
|
||||
Subsystem: "roomserver",
|
||||
Name: "calculate_state_prev_event_length",
|
||||
Help: "The length of the list of events to calculate the state after",
|
||||
},
|
||||
[]string{"algorithm", "outcome"},
|
||||
)
|
||||
|
||||
var calculateStateFullStateLength = prometheus.NewSummaryVec(
|
||||
prometheus.SummaryOpts{
|
||||
Namespace: "dendrite",
|
||||
Subsystem: "roomserver",
|
||||
Name: "calculate_state_full_state_length",
|
||||
Help: "The length of the full room state.",
|
||||
},
|
||||
[]string{"algorithm", "outcome"},
|
||||
)
|
||||
|
||||
var calculateStateConflictLength = prometheus.NewSummaryVec(
|
||||
prometheus.SummaryOpts{
|
||||
Namespace: "dendrite",
|
||||
Subsystem: "roomserver",
|
||||
Name: "calculate_state_conflict_state_length",
|
||||
Help: "The length of the conflicted room state.",
|
||||
},
|
||||
[]string{"algorithm", "outcome"},
|
||||
)
|
||||
|
||||
type calculateStateMetrics struct {
|
||||
algorithm string
|
||||
startTime time.Time
|
||||
prevEventLength int
|
||||
fullStateLength int
|
||||
conflictLength int
|
||||
}
|
||||
|
||||
func (c *calculateStateMetrics) stop(stateNID types.StateSnapshotNID, err error) (types.StateSnapshotNID, error) {
|
||||
var outcome string
|
||||
if err == nil {
|
||||
outcome = "success"
|
||||
} else {
|
||||
outcome = "failure"
|
||||
}
|
||||
endTime := time.Now()
|
||||
calculateStateDurations.WithLabelValues(c.algorithm, outcome).Observe(
|
||||
float64(endTime.Sub(c.startTime).Nanoseconds()) / 1000.,
|
||||
)
|
||||
calculateStatePrevEventLength.WithLabelValues(c.algorithm, outcome).Observe(
|
||||
float64(c.prevEventLength),
|
||||
)
|
||||
calculateStateFullStateLength.WithLabelValues(c.algorithm, outcome).Observe(
|
||||
float64(c.fullStateLength),
|
||||
)
|
||||
calculateStateConflictLength.WithLabelValues(c.algorithm, outcome).Observe(
|
||||
float64(c.conflictLength),
|
||||
)
|
||||
return stateNID, err
|
||||
}
|
||||
|
||||
func init() {
|
||||
prometheus.MustRegister(
|
||||
calculateStateDurations, calculateStatePrevEventLength,
|
||||
calculateStateFullStateLength, calculateStateConflictLength,
|
||||
)
|
||||
}
|
||||
|
||||
// CalculateAndStoreStateBeforeEvent calculates a snapshot of the state of a room before an event.
|
||||
// Stores the snapshot of the state in the database.
|
||||
// Returns a numeric ID for the snapshot of the state before the event.
|
||||
func CalculateAndStoreStateBeforeEvent(
|
||||
db RoomStateDatabase, event gomatrixserverlib.Event, roomNID types.RoomNID,
|
||||
) (types.StateSnapshotNID, error) {
|
||||
// Load the state at the prev events.
|
||||
prevEventRefs := event.PrevEvents()
|
||||
prevEventIDs := make([]string, len(prevEventRefs))
|
||||
for i := range prevEventRefs {
|
||||
prevEventIDs[i] = prevEventRefs[i].EventID
|
||||
}
|
||||
|
||||
prevStates, err := db.StateAtEventIDs(prevEventIDs)
|
||||
if err != nil {
|
||||
return 0, err
|
||||
}
|
||||
|
||||
// The state before this event will be the state after the events that came before it.
|
||||
return CalculateAndStoreStateAfterEvents(db, roomNID, prevStates)
|
||||
}
|
||||
|
||||
// CalculateAndStoreStateAfterEvents finds the room state after the given events.
|
||||
// Stores the resulting state in the database and returns a numeric ID for that snapshot.
|
||||
func CalculateAndStoreStateAfterEvents(db RoomStateDatabase, roomNID types.RoomNID, prevStates []types.StateAtEvent) (types.StateSnapshotNID, error) {
|
||||
metrics := calculateStateMetrics{startTime: time.Now(), prevEventLength: len(prevStates)}
|
||||
|
||||
if len(prevStates) == 0 {
|
||||
// 2) There weren't any prev_events for this event so the state is
|
||||
// empty.
|
||||
metrics.algorithm = "empty_state"
|
||||
return metrics.stop(db.AddState(roomNID, nil, nil))
|
||||
}
|
||||
|
||||
if len(prevStates) == 1 {
|
||||
prevState := prevStates[0]
|
||||
if prevState.EventStateKeyNID == 0 {
|
||||
// 3) None of the previous events were state events and they all
|
||||
// have the same state, so this event has exactly the same state
|
||||
// as the previous events.
|
||||
// This should be the common case.
|
||||
metrics.algorithm = "no_change"
|
||||
return metrics.stop(prevState.BeforeStateSnapshotNID, nil)
|
||||
}
|
||||
// The previous event was a state event so we need to store a copy
|
||||
// of the previous state updated with that event.
|
||||
stateBlockNIDLists, err := db.StateBlockNIDs([]types.StateSnapshotNID{prevState.BeforeStateSnapshotNID})
|
||||
if err != nil {
|
||||
metrics.algorithm = "_load_state_blocks"
|
||||
return metrics.stop(0, err)
|
||||
}
|
||||
stateBlockNIDs := stateBlockNIDLists[0].StateBlockNIDs
|
||||
if len(stateBlockNIDs) < maxStateBlockNIDs {
|
||||
// 4) The number of state data blocks is small enough that we can just
|
||||
// add the state event as a block of size one to the end of the blocks.
|
||||
metrics.algorithm = "single_delta"
|
||||
return metrics.stop(db.AddState(
|
||||
roomNID, stateBlockNIDs, []types.StateEntry{prevState.StateEntry},
|
||||
))
|
||||
}
|
||||
// If there are too many deltas then we need to calculate the full state
|
||||
// So fall through to calculateAndStoreStateAfterManyEvents
|
||||
}
|
||||
|
||||
return calculateAndStoreStateAfterManyEvents(db, roomNID, prevStates, metrics)
|
||||
}
|
||||
|
||||
// maxStateBlockNIDs is the maximum number of state data blocks to use to encode a snapshot of room state.
|
||||
// Increasing this number means that we can encode more of the state changes as simple deltas which means that
|
||||
// we need fewer entries in the state data table. However making this number bigger will increase the size of
|
||||
// the rows in the state table itself and will require more index lookups when retrieving a snapshot.
|
||||
// TODO: Tune this to get the right balance between size and lookup performance.
|
||||
const maxStateBlockNIDs = 64
|
||||
|
||||
// calculateAndStoreStateAfterManyEvents finds the room state after the given events.
|
||||
// This handles the slow path of calculateAndStoreStateAfterEvents for when there is more than one event.
|
||||
// Stores the resulting state and returns a numeric ID for the snapshot.
|
||||
func calculateAndStoreStateAfterManyEvents(
|
||||
db RoomStateDatabase, roomNID types.RoomNID, prevStates []types.StateAtEvent, metrics calculateStateMetrics,
|
||||
) (types.StateSnapshotNID, error) {
|
||||
// Conflict resolution.
|
||||
// First stage: load the state after each of the prev events.
|
||||
combined, err := LoadCombinedStateAfterEvents(db, prevStates)
|
||||
if err != nil {
|
||||
metrics.algorithm = "_load_combined_state"
|
||||
return metrics.stop(0, err)
|
||||
}
|
||||
|
||||
// Collect all the entries with the same type and key together.
|
||||
// We don't care about the order here because the conflict resolution
|
||||
// algorithm doesn't depend on the order of the prev events.
|
||||
// Remove duplicate entires.
|
||||
combined = combined[:util.SortAndUnique(stateEntrySorter(combined))]
|
||||
|
||||
// Find the conflicts
|
||||
conflicts := findDuplicateStateKeys(combined)
|
||||
|
||||
var state []types.StateEntry
|
||||
if len(conflicts) > 0 {
|
||||
metrics.conflictLength = len(conflicts)
|
||||
|
||||
// 5) There are conflicting state events, for each conflict workout
|
||||
// what the appropriate state event is.
|
||||
|
||||
// Work out which entries aren't conflicted.
|
||||
var notConflicted []types.StateEntry
|
||||
for _, entry := range combined {
|
||||
if _, ok := stateEntryMap(conflicts).lookup(entry.StateKeyTuple); !ok {
|
||||
notConflicted = append(notConflicted, entry)
|
||||
}
|
||||
}
|
||||
|
||||
resolved, err := resolveConflicts(db, notConflicted, conflicts)
|
||||
if err != nil {
|
||||
metrics.algorithm = "_resolve_conflicts"
|
||||
return metrics.stop(0, err)
|
||||
}
|
||||
metrics.algorithm = "full_state_with_conflicts"
|
||||
state = resolved
|
||||
} else {
|
||||
metrics.algorithm = "full_state_no_conflicts"
|
||||
// 6) There weren't any conflicts
|
||||
state = combined
|
||||
}
|
||||
metrics.fullStateLength = len(state)
|
||||
|
||||
// TODO: Check if we can encode the new state as a delta against the
|
||||
// previous state.
|
||||
return metrics.stop(db.AddState(roomNID, nil, state))
|
||||
}
|
||||
|
||||
// resolveConflicts resolves a list of conflicted state entries. It takes two lists.
|
||||
// The first is a list of all state entries that are not conflicted.
|
||||
// The second is a list of all state entries that are conflicted
|
||||
// A state entry is conflicted when there is more than one numeric event ID for the same state key tuple.
|
||||
// Returns a list that combines the entries without conflicts with the result of state resolution for the entries with conflicts.
|
||||
// The returned list is sorted by state key tuple.
|
||||
// Returns an error if there was a problem talking to the database.
|
||||
func resolveConflicts(db RoomStateDatabase, notConflicted, conflicted []types.StateEntry) ([]types.StateEntry, error) {
|
||||
|
||||
// Load the conflicted events
|
||||
conflictedEvents, eventIDMap, err := loadStateEvents(db, conflicted)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
// Work out which auth events we need to load.
|
||||
needed := gomatrixserverlib.StateNeededForAuth(conflictedEvents)
|
||||
|
||||
// Find the numeric IDs for the necessary state keys.
|
||||
var neededStateKeys []string
|
||||
neededStateKeys = append(neededStateKeys, needed.Member...)
|
||||
neededStateKeys = append(neededStateKeys, needed.ThirdPartyInvite...)
|
||||
stateKeyNIDMap, err := db.EventStateKeyNIDs(neededStateKeys)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
// Load the necessary auth events.
|
||||
tuplesNeeded := stateKeyTuplesNeeded(stateKeyNIDMap, needed)
|
||||
var authEntries []types.StateEntry
|
||||
for _, tuple := range tuplesNeeded {
|
||||
if eventNID, ok := stateEntryMap(notConflicted).lookup(tuple); ok {
|
||||
authEntries = append(authEntries, types.StateEntry{tuple, eventNID})
|
||||
}
|
||||
}
|
||||
authEvents, _, err := loadStateEvents(db, authEntries)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
// Resolve the conflicts.
|
||||
resolvedEvents := gomatrixserverlib.ResolveStateConflicts(conflictedEvents, authEvents)
|
||||
|
||||
// Map from the full events back to numeric state entries.
|
||||
for _, resolvedEvent := range resolvedEvents {
|
||||
entry, ok := eventIDMap[resolvedEvent.EventID()]
|
||||
if !ok {
|
||||
panic(fmt.Errorf("Missing state entry for event ID %q", resolvedEvent.EventID()))
|
||||
}
|
||||
notConflicted = append(notConflicted, entry)
|
||||
}
|
||||
|
||||
// Sort the result so it can be searched.
|
||||
sort.Sort(stateEntrySorter(notConflicted))
|
||||
return notConflicted, nil
|
||||
}
|
||||
|
||||
// stateKeyTuplesNeeded works out which numeric state key tuples we need to authenticate some events.
|
||||
func stateKeyTuplesNeeded(stateKeyNIDMap map[string]types.EventStateKeyNID, stateNeeded gomatrixserverlib.StateNeeded) []types.StateKeyTuple {
|
||||
var keyTuples []types.StateKeyTuple
|
||||
if stateNeeded.Create {
|
||||
keyTuples = append(keyTuples, types.StateKeyTuple{types.MRoomCreateNID, types.EmptyStateKeyNID})
|
||||
}
|
||||
if stateNeeded.PowerLevels {
|
||||
keyTuples = append(keyTuples, types.StateKeyTuple{types.MRoomPowerLevelsNID, types.EmptyStateKeyNID})
|
||||
}
|
||||
if stateNeeded.JoinRules {
|
||||
keyTuples = append(keyTuples, types.StateKeyTuple{types.MRoomJoinRulesNID, types.EmptyStateKeyNID})
|
||||
}
|
||||
for _, member := range stateNeeded.Member {
|
||||
stateKeyNID, ok := stateKeyNIDMap[member]
|
||||
if ok {
|
||||
keyTuples = append(keyTuples, types.StateKeyTuple{types.MRoomMemberNID, stateKeyNID})
|
||||
}
|
||||
}
|
||||
for _, token := range stateNeeded.ThirdPartyInvite {
|
||||
stateKeyNID, ok := stateKeyNIDMap[token]
|
||||
if ok {
|
||||
keyTuples = append(keyTuples, types.StateKeyTuple{types.MRoomThirdPartyInviteNID, stateKeyNID})
|
||||
}
|
||||
}
|
||||
return keyTuples
|
||||
}
|
||||
|
||||
// loadStateEvents loads the matrix events for a list of state entries.
|
||||
// Returns a list of state events in no particular order and a map from string event ID back to state entry.
|
||||
// The map can be used to recover which numeric state entry a given event is for.
|
||||
// Returns an error if there was a problem talking to the database.
|
||||
func loadStateEvents(db RoomStateDatabase, entries []types.StateEntry) ([]gomatrixserverlib.Event, map[string]types.StateEntry, error) {
|
||||
eventNIDs := make([]types.EventNID, len(entries))
|
||||
for i := range entries {
|
||||
eventNIDs[i] = entries[i].EventNID
|
||||
}
|
||||
events, err := db.Events(eventNIDs)
|
||||
if err != nil {
|
||||
return nil, nil, err
|
||||
}
|
||||
eventIDMap := map[string]types.StateEntry{}
|
||||
result := make([]gomatrixserverlib.Event, len(entries))
|
||||
for i := range entries {
|
||||
event, ok := eventMap(events).lookup(entries[i].EventNID)
|
||||
if !ok {
|
||||
panic(fmt.Errorf("Corrupt DB: Missing event numeric ID %d", entries[i].EventNID))
|
||||
}
|
||||
result[i] = event.Event
|
||||
eventIDMap[event.Event.EventID()] = entries[i]
|
||||
}
|
||||
return result, eventIDMap, nil
|
||||
}
|
||||
|
||||
// findDuplicateStateKeys finds the state entries where the state key tuple appears more than once in a sorted list.
|
||||
// Returns a sorted list of those state entries.
|
||||
func findDuplicateStateKeys(a []types.StateEntry) []types.StateEntry {
|
||||
var result []types.StateEntry
|
||||
// j is the starting index of a block of entries with the same state key tuple.
|
||||
j := 0
|
||||
for i := 1; i < len(a); i++ {
|
||||
// Check if the state key tuple matches the start of the block
|
||||
if a[j].StateKeyTuple != a[i].StateKeyTuple {
|
||||
// If the state key tuple is different then we've reached the end of a block of duplicates.
|
||||
// Check if the size of the block is bigger than one.
|
||||
// If the size is one then there was only a single entry with that state key tuple so we don't add it to the result
|
||||
if j+1 != i {
|
||||
// Add the block to the result.
|
||||
result = append(result, a[j:i]...)
|
||||
}
|
||||
// Start a new block for the next state key tuple.
|
||||
j = i
|
||||
}
|
||||
}
|
||||
// Check if the last block with the same state key tuple had more than one event in it.
|
||||
if j+1 != len(a) {
|
||||
result = append(result, a[j:]...)
|
||||
}
|
||||
return result
|
||||
}
|
||||
|
||||
type stateEntrySorter []types.StateEntry
|
||||
|
||||
func (s stateEntrySorter) Len() int { return len(s) }
|
||||
func (s stateEntrySorter) Less(i, j int) bool { return s[i].LessThan(s[j]) }
|
||||
func (s stateEntrySorter) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
|
||||
|
||||
type stateBlockNIDListMap []types.StateBlockNIDList
|
||||
|
||||
func (m stateBlockNIDListMap) lookup(stateNID types.StateSnapshotNID) (stateBlockNIDs []types.StateBlockNID, ok bool) {
|
||||
|
|
@ -360,3 +740,45 @@ func (s stateBlockNIDSorter) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
|
|||
func uniqueStateBlockNIDs(nids []types.StateBlockNID) []types.StateBlockNID {
|
||||
return nids[:util.SortAndUnique(stateBlockNIDSorter(nids))]
|
||||
}
|
||||
|
||||
// Map from event type, state key tuple to numeric event ID.
|
||||
// Implemented using binary search on a sorted array.
|
||||
type stateEntryMap []types.StateEntry
|
||||
|
||||
// lookup an entry in the event map.
|
||||
func (m stateEntryMap) lookup(stateKey types.StateKeyTuple) (eventNID types.EventNID, ok bool) {
|
||||
// Since the list is sorted we can implement this using binary search.
|
||||
// This is faster than using a hash map.
|
||||
// We don't have to worry about pathological cases because the keys are fixed
|
||||
// size and are controlled by us.
|
||||
list := []types.StateEntry(m)
|
||||
i := sort.Search(len(list), func(i int) bool {
|
||||
return !list[i].StateKeyTuple.LessThan(stateKey)
|
||||
})
|
||||
if i < len(list) && list[i].StateKeyTuple == stateKey {
|
||||
ok = true
|
||||
eventNID = list[i].EventNID
|
||||
}
|
||||
return
|
||||
}
|
||||
|
||||
// Map from numeric event ID to event.
|
||||
// Implemented using binary search on a sorted array.
|
||||
type eventMap []types.Event
|
||||
|
||||
// lookup an entry in the event map.
|
||||
func (m eventMap) lookup(eventNID types.EventNID) (event *types.Event, ok bool) {
|
||||
// Since the list is sorted we can implement this using binary search.
|
||||
// This is faster than using a hash map.
|
||||
// We don't have to worry about pathological cases because the keys are fixed
|
||||
// size are controlled by us.
|
||||
list := []types.Event(m)
|
||||
i := sort.Search(len(list), func(i int) bool {
|
||||
return list[i].EventNID >= eventNID
|
||||
})
|
||||
if i < len(list) && list[i].EventNID == eventNID {
|
||||
ok = true
|
||||
event = &list[i]
|
||||
}
|
||||
return
|
||||
}
|
||||
|
|
|
|||
|
|
@ -12,7 +12,7 @@
|
|||
// See the License for the specific language governing permissions and
|
||||
// limitations under the License.
|
||||
|
||||
package input
|
||||
package state
|
||||
|
||||
import (
|
||||
"github.com/matrix-org/dendrite/roomserver/types"
|
||||
Loading…
Reference in a new issue